Digatron DT-31K2 Operating Instructions

OPERATING INSTRUCTIONS MODEL DT-31K2
KEYBOARD CONFIGURATION
DIGATRON MODEL DT-31
TACH / EGT
POWER
MODE
ON
POWER ON
When turned on, your instrument will begin a 10 second
display test. At the end of the test, your instrument's serial
number will be displayed. To bypass this test press the
MODE button.
SETTING FUNCTION LIMITS
Before using your DT-31K2, be sure to set the operating
limits for each sensor. The instrument will not allow limits to
be set while the engine is running. This is to prevent
possible damage to your instrument.
Limits allow the instrument to give you a visual warning if
any of the inputs exceed their limit. Limits should be set at
levels that allow you to react to the visual warning before
engine damage occurs. You will also need to set a calibration
number so the instrument can display the correct RPM.
To set the limits, the instrument must be turned on and the
kart's engine turned off. Press and hold the MAXIMUM
RECALL and MEMORY RECALL buttons simultaneously
until the display flashes. This will put the instrument into the
Set Limits mode of operation, which is indicated by the
display flashing. To increase the limit, press the MAXIMUM
RECALL button. To decrease the limit, press the MEMORY
RECALL button. To increase or decrease the limit by a large
amount, press and hold either the MAXIMUM RECALL or
the MEMORY RECALL button until the approximate limit
value is reached. When finished setting the tach limit, press
the MODE button to set the EGT limit. Set limits at levels
high enough for normal operation, but not so high that
engine damage can occur before you can respond to a
problem.
The tach limit requires the setting of two separate
parameters. The first is the maximum RPM for safe engine
operation. The second number is for tach calibration. In order
to display the correct RPM for different engine types, the
instrument divides the tach input signal by the tach
calibration number. This number can be between .5 and 31.
Select this number so that it will provide the correct display
for your application using the MAXIMUM RECALL and
MEMORY RECALL buttons.
The most frequently used numbers are:
.5 - for some single cylinder 4 cycle motors
1 - for single cylinder 2 cycle and some 4 cycle motors
MAXIMUM MEMORY STORE
RECALL RECALL CLEAR
SET LIMITS POWER OFF
2 - for 2 cylinder 2 cycle and 4 cylinder 4 cycle motors
If you are unsure of the exact tach calibration number for
your engine, experiment. If your calibration number is
currently set at 1 and the RPM displayed is double what it
should be, set the calibration number to 2. Alternately, if the
RPM displayed is half of the correct value, decrease the
calibration number to half of the current number.
To save the current limits and exit the Set Limits mode, press
the STORE button or switch.
EXHAUST GAS TEMPERATURE
Exhaust gas temperature (EGT) is used primarily for adjusting
the air/fuel ratio. Because of its quick response, the effects of
carburetor adjustments are seen immediately. Fuel system
and carburetor problems can often be spotted quickly
enough to prevent engine damage.
Exhaust gas temperatures typically run between 1100°F and
1350°F. The EGT on a properly tuned engine will increase
rapidly as the throttle is opened and as the load on the
engine is increased. At full throttle and full load the EGT will
stabilize at a temperature dependent on the air/fuel ratio.
Both a "too lean" or a "too rich" condition will be indicated
by a lower than peak temperature. The "too lean" condition
can damage your engine. An increase in coolant temperature
or cylinder head temperature is usually an indication of this.
The best way to determine what temperature is normal for
your motor is to tune for good plug or piston color and then
observe the temperature at various throttle settings.
TACHOMETER
The tach displays RPM in thousands of RPM.
For example, if your display shows 9.50, your RPM is 9500
RPM.
MODE BUTTON
During operation, the MODE button is used to change from
the primary to the secondary function in the display. When
the instrument is first turned on, the primary function (tach)
is displayed. The secondary function (EHT) operates in the
background until the MODE button is pressed, or until it's
limit is exceeded.
STORING DATA
The STORE button or the optional REMOTE STORE
switch can be pressed up to three different times to store the
current values of each function into memory. The display
and the optional WARNING INDICATOR LIGHT will flash
to indicate a successful store of information. After three sets
of numbers are stored, additional attempts to store
information will be ignored. In addition, the instrument
automatically stores a maximum value for each sensor during
the current recording period.